these cards are basically extra lands you can play, and they synergize with artifact payoffs or anything that cares about casting spells, like storm abilities
If the spell or ability that's copied has damage divided as it was cast or activated, the division can't be changed (although the targets receiving that damage still can)
When it comes to pure power, though, nothing matches Maleficent, Monstrous Dragon
The Golden Throne offers a unique effect and is a sacrifice outlet with a mana payoff that will be relatively easy to take advantage of
It effectively shrinks your deck so that instead of running 60 cards, you can run 56 (with some little timing hiccups)
This is a case where the Japanese version might just be better than the English version simply for including more of the original cards features